MC68HC08AS32A Datasheet, PDF (152/296 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Programmable Interrupt Timer (PIT)
Address: $004B
Bit 7
6
5
4
3
2
1
Bit 0
Read: POF
0
0
POIE PSTOP
PPS2
PPS1
PPS0
Write: 0
PRST
Reset: 0
0
1
0
0
0
0
0
= Unimplemented
Figure 11-3. PIT Status and Control Register (PSC)
NOTE:
NOTE:
POF — PIT Overflow Flag Bit
This read/write flag is set when the PIT counter reaches the modulo value
programmed in the PIT counter modulo registers. Clear POF by reading the PIT
status and control register when POF is set and then writing a logic 0 to POF. If
another PIT overflow occurs before the clearing sequence is complete, then
writing logic 0 to POF has no effect. Therefore, a POF interrupt request cannot
be lost due to inadvertent clearing of POF. Reset clears the POF bit. Writing a
logic 1 to POF has no effect.
1 = PIT counter has reached modulo value
0 = PIT counter has not reached modulo value
POIE — PIT Overflow Interrupt Enable Bit
This read/write bit enables PIT overflow interrupts when the POF bit becomes
set. Reset clears the POIE bit.
1 = PIT overflow interrupts enabled
0 = PIT overflow interrupts disabled
PSTOP — PIT Stop Bit
This read/write bit stops the PIT counter. Counting resumes when PSTOP is
cleared. Reset sets the PSTOP bit, stopping the PIT counter until software
clears the PSTOP bit.
1 = PIT counter stopped
0 = PIT counter active
Do not set the PSTOP bit before entering wait mode if the PIT is required to exit
wait mode.
PRST — PIT Reset Bit
Setting this write-only bit resets the PIT counter and the PIT prescaler. Setting
PRST has no effect on any other registers. Counting resumes from $0000.
PRST is cleared automatically after the PIT counter is reset and always reads
as logic zero. Reset clears the PRST bit.
1 = Prescaler and PIT counter cleared
0 = No effect
Setting the PSTOP and PRST bits simultaneously stops the PIT counter at a value
of $0000.
Data Sheet
152
Programmable Interrupt Timer (PIT)
For More Information On This Product,
Go to: www.freescale.com
MC68HC08AS32A — Rev. 1
MOTOROLA